Various pressure-volume-temperature (PVT) measurements can be performed to define physical properties of hydrocarbon reservoir fluids (gases, liquids, and occasionally solids). These measurements can be performed in large, fixed laboratories employing a number of individual pieces of equipment. Early (and some current) PVT cells utilized mercury as a pressurizing and mixing medium within a temperature controlled pressure vessel. Mercury-free units were developed in the early 1990's using either a floating piston or a mechanical screw to change sample volume and thereby, pressure. Both of these types of vessels used mechanical stirring to mix the contained sample. Traditional and currently commercially available PVT cells typically have “windows” to allow viewing of the cell's contents for phase determination and volume measurement and are typically limited to pressure ratings less than 15,000 pounds per square inch (psi).